Temperature-dependent structural behavior of self-avoiding walks on three-dimensional Sierpinski sponges

2010 ◽  
Vol 81 (5) ◽  
Author(s):  
Miriam Fritsche ◽  
Dieter W. Heermann
2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Thomas Fellner ◽  
Elena Zukowski ◽  
Jürgen Wilde ◽  
H. Kück ◽  
H. Richter ◽  
...  

This investigation is aimed at the modeling of both the fabrication process and the reliability of press-fit interconnections on moulded interconnect devices (MID). These are multifunctional three-dimensional substrates, produced by thermoplastic injection moulding for large-series applications. The assembly process and subsequently the durability of press-fit interconnections has been modeled and proved with a finite element software. Especially, a simulation tool for process optimizations was created and applied. In order to obtain realistic results, a creep model for the investigated base material, a liquid-crystal polymer (LCP), was generated and verified by experiments. Required friction coefficients between metal pin and base material were determined by adapting simulations and experiments. Retention forces of pins pressed into substrate holes during as well after the assembly process, and after temperature loads were predicted by simulations. Additionally, the decreasing extraction forces over time due to creep in the thermoplastic base material have been predicted for different storage temperatures as well with finite element analyses. Following, the numerical results of the process and reliability modeling were verified by experiments. It is concluded that the behavior of the mechanical contact of the pin-substrate system, can be suitably described time- and temperature-dependent.


1976 ◽  
Vol 54 (14) ◽  
pp. 1454-1460 ◽  
Author(s):  
T. Tiedje ◽  
R. R. Haering

The theory of ultrasonic attenuation in metals is extended so that it applies to quasi one and two dimensional electronic systems. It is shown that the attenuation in such systems differs significantly from the well-known results for three dimensional systems. The difference is particularly marked for one dimensional systems, for which the attenuation is shown to be strongly temperature dependent.


2006 ◽  
Vol 61 (7) ◽  
pp. 792-798 ◽  
Author(s):  
Klaus Müller-Buschbaum

The reaction of a melt of unsubstituted imidazole with praseodymium metal yields bright green crystals of 3D-[Pr(Im)3(ImH)]@ImH. Imidazolate ligands coordinate η1 via both N atoms their 1,3 positioning within the heterocycle being responsible for the connection of praseodymium atoms. A 3-dimensional network is formed with imidazole molecules from the melt intercalated in the crystal structure. The imidazole molecules can be released and temperature dependent reversibly be exchanged with gas molecules including argon. Thus the solvent free high temperature synthesis of rare earth elements with amine melts can also be utilized for “crystal engineering” and the synthesis of compounds with material science aspects. Furthermore 3D-[Pr(Im)3(ImH)]@ImH is the first unsubstituted imidazolate of the lanthanides.


1977 ◽  
Vol 18 (80) ◽  
pp. 373-389 ◽  
Author(s):  
D. Jenssen

AbstractA three-dimensional model of the temperature and velocity distribution within any arbitrary-shaped ice mass is described. There is a mutual interaction in the model between the flow of the ice and its thermodynamics, since the flow law used in the model is temperature-dependent.Ice growth in three dimensions is governed by mass accumulation through precipitation, by mass depletion through loss of ice over the ocean, and by continuity requirements. Phase changes at the base of the ice are accounted for. The model has been applied in art exploratory manner to the Greenland ice sheet. Changes in the ice shape and temperature are presented and discussed. The basic shortcoming of the model as here presented appears primarily due to the coarse finite-difference mesh used, and to an unsophisticated approach to modelling the boundary ice.


2018 ◽  
Vol 22 (09n10) ◽  
pp. 821-830 ◽  
Author(s):  
Zheng Wang ◽  
Jian-Hua Zhang ◽  
Cheng-Yi Zhu ◽  
Shao-Yun Yin ◽  
Mei Pan

Bipodal ligand 5,15-bis(4-carboxyphenyl) porphyrin (H[Formula: see text]DCPP) was designed and synthesized. By adjusting the molar ratio of H[Formula: see text]DCPP, ancillary ligand 4,4-bipyridine (bpy) and zinc acetate salts, three novel coordination assemblies, namely, zero-dimensional dimeric [Zn[Formula: see text](H[Formula: see text]DCPP)[Formula: see text] ·bpy] ·4H[Formula: see text]O ·4DMF (Zn-D), two-dimensional polymeric {[Zn[Formula: see text](DCPP) ·bpy[Formula: see text] ·H[Formula: see text]O ·DMF[Formula: see text]] ·solvent}[Formula: see text] (Zn-2D), and three-dimensional polymeric [Zn[Formula: see text](DCPP) ·bpy[Formula: see text]][Formula: see text] (Zn-3D) were assembled. Due to the delicate integration of multiple chromophores in the coordination space combining bpy, DCPP and MLCT emissions together, photoluminescence (PL) of the three porphyrin-zinc coordination assemblies differ from each other and color tone is tunable from blue to orange with changes of the excitation wavelength. In particular, white light emission (WLE) can be observed by the excitation of 270 to 290 nm, representing the first examples of single component WLE compounds based on porphyrin ligands. Furthermore, temperature-dependent luminescence results in a linear [Formula: see text]–[Formula: see text] relationship in Zn-2D and Zn-3D assemblies, applicable for long wavelength red-emitting thermometers.


Author(s):  
Judith Bönnighausen ◽  
Stefan Seidel ◽  
Steffen Klenner ◽  
Rainer Pöttgen

Abstract The ternary platinides CaGa5Pt3 (a = 2082.5(4), b = 406.05(8), c = 739.2(1) pm) and EuGa5Pt3 (a = 2085.5(5), b = 412.75(9), c = 738.7(1) pm) were synthesized from the elements in sealed high-melting metal tubes in an induction furnace. CaGa5Pt3 and EuGa5Pt3 are isotypic with CeAl5Pt3 and isopointal with the YNi5Si3 type intermetallic phases (space group Pnma, oP36 and Wyckoff sequence c 9). The structure of EuGa5Pt3 was refined from single crystal X-ray diffractometer data: wR2 = 0.0443, 1063 F 2 values and 56 variables. The gallium and platinum atoms build up a three-dimensional [Ga5Pt3]2− polyanionic network in which the europium atoms fill slightly distorted hexagonal prismatic voids. The Ga–Pt distances within the network range from 249 to 271 pm, emphasizing the covalent bonding character. Temperature dependent magnetic susceptibility measurements indicate diamagnetism for CaGa5Pt3 and isotypic BaGa5Pt3. EuGa5Pt3 behaves like a Curie–Weiss paramagnet above 50 K with an experimental magnetic moment of 8.17(1) µB/Eu atom, indicating divalent europium. Antiferromagnetic ordering sets in at T N = 8.5(1) K. The divalent ground state of europium is confirmed by 151Eu Mössbauer spectroscopy. EuGa5Pt3 shows a single signal at 78 K with an isomer shift of −9.89(4) mm s−1. Full magnetic hyperfine splitting with a hyperfine field of 25.0(2) T is observed at 6 K in the magnetically ordered regime.


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